Loopback-Detection Control Enable; Loopback-Detection Enable - H3C S5120-SI Series Command Reference Manual

loopback-detection control enable

Syntax
loopback-detection control enable
undo loopback-detection control enable
View
Ethernet port view
Default Level
2: System level
Parameters
None
Description
Use the loopback-detection control enable command to enable loopback detection for a trunk port or
hybrid port.
Use the undo loopback-detection control enable command to restore the default.
By default, loopback detection for a trunk port or hybrid port is disabled.
With loopback detection enabled, when the device detects a loop on a port, the device puts the port
in control mode. In this mode, inbound packets on the port are all discarded, while outbound
packets on the port are forwarded normally. Meanwhile, the device sends trap messages to the
terminal, and deletes the corresponding MAC address forwarding entry.
With loopback detection disabled, when the device detects a loop on a port, it only sends a trap
message to the terminal. In the mean time, the port still works normally.
Note that this command is not applicable to an access port as loopback detection is enabled on it by
default.
Examples
# Enable loopback detection control on trunk port GigabitEthernet 1/0/1.
<Sysname> system-view
[Sysname] loopback-detection enable
[Sysname] interface gigabitethernet 1/0/1
[Sysname-GigabitEthernet1/0/1] port link-type trunk
[Sysname-GigabitEthernet1/0/1] loopback-detection enable
[Sysname-GigabitEthernet1/0/1] loopback-detection control enable

loopback-detection enable

Syntax
loopback-detection enable
undo loopback-detection enable
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